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Roofing/Ridge venting an R panel metal roof


I woud like to put a ridge vent on my new R panel metal roof I have a 4/12 pitch and I havent installed my ridge cap yet but it over laps 6 inches on each side.what do you recommend and where can I find it? I'm in Arizona and I do get a monsoon season from July to September with heavy rain and wind.
Thanks in advance Tim

The answer is that it depends. The size of the vent is dependent on the square footage of the area that it is venting. There are many manufacturers out there of roof vents, such as Air Vent, GAF, Owens Corning, and they can be purchased through your local roofing distributor.
You should first calculate the attic space that is being vented and divide that number by 150 which will give you the total net-free-ventilating-area (NFVA) that you require (in square feet). I recommend that you convert that to square-inches. You should examine the intake (typically eave vents) to determine the square-inches of intake, and the remainder will be what you need for the exhaust. The manufacturer's will provide the NFVA/lineal foot for their products.


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Aaron Nelson


All types of questions with regard to roofing, waterproofing and sheet metal. This includes commercial and residential buildings, along with the various aspects of the construction means and methods, ventilation, steep-slope or low-slope, code requirements, installation errors and other such problems


I started in roofing fabricating and installing sheet metal flashings out of high school for a large commercial contractor. I worked for the same contractor in the office estimating and project managing commercial project for 10 years. I left the construction side of roofing and now work as a roof consultant, which I have been doing for 8-years.

RCI, Inc.

I am a Registered Roof Consultant (RRC) and a Registered Roof Observer (RRO) through RCI, Inc. RCI is a international group of building envelope professionals. I am an approved instructor for RCI educational programs.

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We have worked with many local school districts, insurance companies, HOA's, building management companies, and we have a national client with buildings located throughout the US.

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